Fig. 1.

Response of sperm from the coral Montipora capitata to ammonium chloride (NH₄Cl) treatment and sAC inhibition. (A) Coral sperm motility (solid line) and pH_i (dashed line) after exposure of sperm in NaFSW to 20 mM NH₄Cl (n ≥ 15 cells per time point). Gray shaded region indicates 99% CI of sperm initial pH_i prior to activation (7.52 ± 0.05). (B) Concentration of cAMP in coral sperm in NaFSW following treatment with 20 mM NH₄Cl (black squares) or control (open squares). cAMP levels are normalized to total protein. (C) Circular motility of coral sperm in NaFSW preincubated with 0.2% DMSO (black) or 50 µM sAC inhibitor KH7 (gray) before and after treatment with NH₄Cl. The horizontal black bar represents the mean of n ≥ 3 replicates. (D) The median speed of coral sperm in seawater pretreated with 0.2% DMSO or 50 µM KH7. The horizontal black bar represents the mean of n = 5 replicates. Error bars in A, C, and D indicate SEM; error bars in B indicate SD; where not visible, they fall within the symbol. Significance is denoted as n.s. (no significance), *P ≤ 0.05, **P ≤ 0.01.